The US Food and Drug Administration approved tiratricol (Emcitate) tablets for oral suspension to treat peripheral thyrotoxicosis in patients with monocarboxylate transporter 8 deficiency, also known as Allan-Herndon-Dudley syndrome, according to an FDA press release.
Monocarboxylate transporter 8 (MCT8) deficiency primarily affects male patients and is caused by a faulty gene that provides instructions for producing the MCT8 transporter, a protein responsible for transporting thyroid hormone into the brain. When the MCT8 transporter does not function properly, insufficient thyroid hormone reaches the brain while excess thyroid hormone accumulates in the bloodstream. Patients may experience an inability to walk or sit independently, absent or severely limited speech, intellectual disability, feeding difficulties, and chronic stress on the heart and metabolism. According to the FDA, tiratricol can enter cells without relying on the MCT8 transporter, thereby reducing elevated thyroid hormone levels in the blood.
“The challenge in treating MCT8 deficiency has always been that the protein needed to deliver thyroid hormone into cells is the one that isn’t working,” said Hylton V. Joffe, MD, director of the Office of Cardiology, Hematology, Endocrinology, and Nephrology in the FDA’s Center for Drug Evaluation and Research. Dr. Joffe continued, “This drug sidesteps that problem, as its active ingredient, tiratricol, can enter cells on its own without relying on the broken transporter, leading to a decrease in the elevated blood thyroid hormone levels.”
Two clinical studies supported the efficacy assessment of tiratricol, including a randomized, placebo-controlled international trial and a longer-term open-label study, with enrollment spanning infants through adults. Treatment lowered circulating thyroid hormone levels in both studies, with changes also observed in heart rate and systolic blood pressure as well as other cardiovascular and metabolic symptoms associated with thyroid hormone levels.
Tiratricol is administered once daily as a liquid suspension by mouth or through a feeding tube in patients with difficulty swallowing. The most common adverse effects were listed as diarrhea, vomiting, rash, and excessive sweating. According to the FDA, patients receiving another thyroid medication should consult their health care provider prior to starting tiratricol because the medications should not be used together.
Tiratricol received Orphan Drug, Rare Pediatric Disease, Fast Track, and Breakthrough Therapy designations as well as Priority Review. The approval was granted to Egetis Therapeutics US Inc.
Source: US Food and Drug Administration